Liquid crystal coating apparatus and liquid crystal coating method

ABSTRACT

The present invention provides a liquid crystal (LC) coating apparatus and an LC coating method. The LC coating apparatus comprises a plurality of liquid crystal coating devices, at least one real-time detector and a controller. The LC coating method comprises the following steps: utilizing the LC coating devices to coat a LC on a substrate; utilizing the real-time detector to real-time detect the LC coated on the substrate and outputting a detection signal; and utilizing the controller to control the LC coating devices according to the detection signal. The present invention can real-time monitor the coating status of the LC for coating and forming a uniform LC film.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation application of U.S. patentapplication Ser. No. 13/000,379, filed on Dec. 21, 2010, the disclosureof which is incorporated herein by reference.

FIELD OF THE INVENTION

The present invention relates to a liquid crystal (LC) coating apparatusand an LC coating method, and more particularly to an LC coatingapparatus and an LC coating method capable of real-time monitoring theLC coating status and forming a uniform LC film.

BACKGROUND OF THE INVENTION

Liquid crystal displays (LCDs) have been widely applied in electricalproducts. Currently, most of LCDs are backlight type LCDs which comprisean LC panel and a backlight module.

The LC panel is composed of two transparent substrates and an LC sealedthere-between. In an assembly process of the LC panel, the LC is filledand sealed between the transparent substrates. Currently, the methodsfor filling the LC between the transparent substrates may be a vacuumsiphon method and a one-drop filling (ODF) method.

However, the filling time of the conventional vacuum siphon method istoo long, and thus the vacuum siphon method can be not applicable tolarge-scale panels. Furthermore, the machine used for the ODF method istoo expensive, and the process thereof is more complicated. Besides,when the dispensed amount (about 0.5 mg˜1.5 mg) of the LC is notprecise, the problems of bubbles or non-uniform coating are susceptibleto arise.

As a result, it is necessary to provide an LC coating apparatus and anLC coating method to solve the problems existing in the conventionaltechnologies, as described above.

SUMMARY OF THE INVENTION

A primary object of the present invention is to provide a liquid crystalcoating apparatus, and the liquid crystal coating apparatus comprises: aplurality of liquid crystal coating devices configured to coat a liquidcrystal on a substrate, wherein the liquid crystal coating devices areinkjet printing heads or slit coating heads; at least one real-timedetector disposed at one side of the liquid crystal coating devicesconfigured to real-time detect the liquid crystal coated on thesubstrate and output a detection signal; and a controller configured tocontrol the liquid crystal coating devices according to the detectionsignal.

Another object of the present invention is to provide a liquid crystalcoating method, and the method comprises the following steps: utilizinga plurality of liquid crystal coating devices to coat a liquid crystalon a substrate, wherein the liquid crystal coating devices are inkjetprinting heads or slit coating heads; utilizing at least one real-timedetector to real-time detect the liquid crystal coated on the substrateand outputting a detection signal; and utilizing a controller to controlthe liquid crystal coating devices according to the detection signal.

In one embodiment of the present invention, the liquid crystal coatingdevices are piezoelectric droplet ejectors, and the controller adjusts avoltage of the liquid crystal coating devices according to a relationbetween a droplet amount and the voltage.

In one embodiment of the present invention, the real-time detector is atleast one charge coupled device configured to real-time detect theliquid crystal coated on the substrate and output the detection signalto the controller, and the detection signal is a real-time image signal,and the controller implements an image gray-scale comparison processingfor the real-time image signal outputted from the real-time detector, soas to calculate the actual weight, number, size or position of theliquid crystal coated on the substrate.

In one embodiment of the present invention, the liquid crystal coatingdevices are the slit coating heads, and the liquid crystal coatingapparatus further comprises a plurality of measuring cylinders, apumping device and a liquid crystal tank, and the measuring cylindersare connected to the liquid crystal coating devices respectivelyconfigured to provide the liquid crystal to the liquid crystal coatingdevices, and the pumping device is connected between the measuringcylinders and the liquid crystal tank for pumping the liquid crystalfrom the liquid crystal tank to the measuring cylinders.

In one embodiment of the present invention, the liquid crystal amount ofeach of the measuring cylinders is a liquid crystal coated amount forone or more liquid crystal units.

In one embodiment of the present invention, the controller adjusts amoving speed of the liquid crystal coating devices, a pressure of themeasuring cylinders, a slit width of the slit coating heads or a pitchbetween each two of liquid crystal units by calculating a liquid crystalamount for the liquid crystal units and a moving distance in coating.

In one embodiment of the present invention, the liquid crystal coatingdevices are the inkjet printing heads, and the liquid crystal coatingmethod further comprises the following step: before coating the liquidcrystal on the substrate, ensuring whether a number and a weight ofliquid crystal droplets ejected by the liquid crystal coating devicessatisfy a predetermined requirement.

In one embodiment of the present invention, the liquid crystal coatingdevices are the inkjet printing heads, and the controller calculates thenumber of the droplets of the liquid crystal ejected by the liquidcrystal coating devices according to the real-time image signal, andimplements a comparison between the number and a predetermined dropletnumber, and then adjusts the ejection of the liquid crystal coatingdevices according to a comparison result.

The LC coating apparatus and the LC coating method of the presentinvention can rapidly coat and form the LC film on the transparentsubstrate, thereby considerably raising the production efficiency andsimplifying the manufacturing process to reduce the labor and time.Furthermore, the problems of bubbles or non-uniform LC film can beimproved by the LC coating apparatus of the present invention, and inthis way, the LC coated amount, thickness and uniformity can beprecisely controlled.

The structure and the technical means adopted by the present inventionto achieve the above and other objects can be best understood byreferring to the following detailed description of the preferredembodiments and the accompanying drawings.

DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic diagram showing an LC coating apparatus accordingto a first embodiment of the present invention;

FIG. 2 is a flow diagram showing an LC coating method according to thefirst embodiment of the present invention;

FIG. 3A is a schematic diagram showing an LC coating apparatus accordingto a second embodiment of the present invention; and

FIG. 3B is a partially schematic diagram showing an LC coating apparatusaccording to the second embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The following embodiments are referring to the accompanying drawings forexemplifying specific implementable embodiments of the presentinvention. Furthermore, directional terms described by the presentinvention, such as upper, lower, front, back, left, right, inner, outer,side and etc., are only directions by referring to the accompanyingdrawings, and thus the used directional terms are used to describe andunderstand the present invention, but the present invention is notlimited thereto.

In the drawings, structure-like elements are labeled with like referencenumerals.

Referring to FIG. 1, a schematic diagram showing an LC coating apparatusaccording to a first embodiment of the present invention is illustrated.The LC coating apparatus 100 of the present embodiment may be configuredto coat and form an LC 101 between two transparent substrates 102,thereby forming an LC display panel. The LC coating apparatus 100comprises a plurality of LC coating devices 110, a plurality ofreal-time detectors 120 and a controller 130. The LC coating devices 110are configured to coat the LC 101 on one of the transparent substrates102, wherein the LC coating devices 110 may be inkjet printing heads orslit coating heads. The real-time detectors 120 are disposed at one sideof the LC coating devices 110 configured to real-time detect the statusof the LC coated on the transparent substrate 102 and output a detectionsignal to the controller 130. The controller 130 is electricallyconnected to the LC coating devices 110 and the real-time detectors 120and can control the coating of the LC coating devices 110 according tothe detection signal outputted from the real-time detectors 120.

Referring to FIG. 1 again, in this embodiment, the LC coating devices110 may be, for example, the inkjet printing heads configured to ejectdroplets of the LC 101 with a high density on a transparent substrate102, wherein the weight of each droplet of the LC 101 ejected by the LCcoating devices 110 may be less than 1 mg, preferably less than 0.1 mg.A pitch between each two adjacent droplets of the LC 101 ejected by theLC coating devices 110 may be less than 1 mm, preferably less than 200μm. The droplets of the LC 101 ejected by the LC coating devices 110 arearranged on the transparent substrate 102 densely, thus naturallyspreading as a uniform LC film under the action of the surface tensionfor significantly improving the non-uniform droplet problem of theconventional ODF method.

Referring to FIG. 1 again, the LC coating devices 110 of the presentembodiment may be, for example, piezoelectric droplet ejectors which cancontrol the amount or size of the droplets ejected by the LC coatingdevices 110 using a voltage. In this embodiment, the droplet amountejected by each droplet ejector can be measured in advance, so as toobtain a relation between the droplet amount of each ejector and thevoltage. Normally, the droplet amount of each ejector is proportional tothe voltage. Subsequently, the voltage of each of the ejectors can beadjusted according to the relation between the droplet amount and thevoltage, thereby allowing the droplet amount ejected by each of theejectors (the LC coating devices 110) being identical.

Referring to FIG. 1 again, the real-time detectors 120 of the presentembodiment are configured to real-time monitor the coating status of theLC coating devices 110, such as the weight, number, size or position ofthe LC coated on the transparent substrate 102, and the real-timedetectors 120 can output the detection signal to the controller 130. Inthis embodiment, the real-time detectors 120 may be, for example, chargecoupled devices (CCD) disposed at one side of each of the LC coatingdevices 110 for real-time detecting the LC coated on the transparentsubstrate 102, and the real-time detectors can transmit a real-timeimage signal (the detection signal) to the controller 130.

Referring to FIG. 1 again, the controller 130 of the present embodimentcan control the coating of the LC coating devices 110 according to thedetection signal outputted from the real-time detectors 120. In thisembodiment, the controller 130 can implement an image gray-scalecomparison processing for the real-time image signal (the detectionsignal) outputted from the real-time detectors 120, so as to calculatethe actual weight, number, size or position of the LC coated on thetransparent substrate 102. Subsequently, according to the actual coatingstatus of the LC coated on the transparent substrate 102, the controller130 may, for example, adjust the voltage of the LC coating devices 110,so as to adjust the LC amount ejected by the LC coating devices 110.

Referring to FIG. 2, a flow diagram showing an LC coating methodaccording to the first embodiment of the present invention isillustrated. When utilizing the LC coating apparatus 100 of the presentembodiment to coat and form the LC 101 on the transparent substrate 102,the LC coating method of the present embodiment may comprise thefollowing steps: utilizing the LC coating devices 110 to coat the LC 101on the transparent substrate 102 (step S201); utilizing the real-timedetectors 120 to real-time detect the LC coated on the transparentsubstrate 102 and outputting the detection signal (step S202); andutilizing the controller 130 to control the LC coating devices 110according to the detection signal (step S203). Before the step S201, forexample, the real-time detectors 120 can be utilized to detect thenumber of the LC droplets ejected by the LC coating devices 110 inadvance, and the weight of the LC droplets can be measured, so as toensure whether the number and weight of the LC droplets ejected by theLC coating devices 110 satisfy a predetermined requirement. In the stepS201, the LC coating devices 110 can move toward a predetermineddirection, and thus the LC coating devices 110 can coat the LC 101 onthe transparent substrate 102 toward the predetermined direction. In thestep S202, for example, the real-time detectors 120 may real-time recordan image of the droplets of the LC 101 on the transparent substrate 102and output the real-time image signal (the detection signal) to thecontroller 130. In the step S203, for example, the controller 130 maycalculate the number of the droplets of the LC 101 ejected by the LCcoating devices 110 according to real-time image signal, and implement acomparison between the number and a predetermined droplet number, andthen adjust the ejection (coating) of the LC coating devices 110according to the comparison result.

Therefore, the LC coating apparatus 100 of the present embodiment canutilize the inkjet printing heads to coat and form a uniform LC film onone transparent substrate 102, and another transparent substrate 102 canbe assembled on the transparent substrate 102 with the LC film using asealant, thereby forming the LC display panel.

Referring to FIG. 3A and FIG. 3B, schematic diagrams showing an LCcoating apparatus according to a second embodiment of the presentinvention are illustrated. The LC coating apparatus 200 of the secondembodiment comprises a plurality of LC coating devices 210, a pluralityof real-time detectors 220 and a controller 230, a plurality ofmeasuring cylinders 240, a pumping device 250 and an LC tank 260. The LCcoating devices 210 are configured to coat the LC 101 on the transparentsubstrate 102, wherein the LC coating devices 210 may be, for example,slit coating heads. The real-time detectors 220 are disposed at one sideof the LC coating devices 210 configured to real-time detect the statusof the LC coated on the transparent substrate 102 and output a detectionsignal to the controller 230, wherein the real-time detectors 220 may beimage sensors disposed at one side of each LC coating device 210 andcapable of laterally moving when coating the LC (referring to FIG. 3B),so as to real-time detect whether the flow rate of the LC ejected by theLC coating devices 210 is uniform, thereby real-time detecting the LCfilm coated by the slit coating heads 210 and outputting a real-timeimage signal (the detection signal) to the controller 230. Thecontroller 230 can implement an image processing for the detectionsignal outputted from the real-time detectors 220, so as to obtain areal-time LC coating amount and control the ejection amount or coatingof the LC coating devices 210.

Referring to FIG. 3A again, the measuring cylinders 240 are connected tothe LC coating devices 210 respectively configured to provide the LC 101to the LC coating devices 210, and thus the LC coating devices 210 cancoat the LC 101 on the transparent substrate 102. In this embodiment,the measuring cylinders 240 may include sensors (not shown) fordetecting the LC amount within the measuring cylinders 240. Therefore,the LC amount provide by the measuring cylinders 240 to the LC coatingdevices 210 can be obtained for monitoring the LC amount within themeasuring cylinders 240 and the coating amount of the LC coating devices210. In this case, the measuring cylinders 240 can provide the LC 101 tothe LC coating devices 210 by a pressure of a gas (such as N₂). Thepumping device 250 may be, for example, a pump connected between themeasuring cylinders 240 and the LC tank 260 for pumping the LC from theLC tank 260 to the measuring cylinders 240. The LC tank 260 is connectedto the pumping device 250 for storing the LC.

Referring to FIG. 3A again, when utilizing the LC coating apparatus 100of the present embodiment to coat and form the LC 101 on the transparentsubstrate 102, firstly, the pumping device 250 can pump the LC from theLC tank 260 to the measuring cylinders 240, wherein the LC amount ofeach of the measuring cylinders 240 may be the LC coated amount for oneor more LC units (LC display panels). Subsequently, the measuringcylinders 240 can provide the LC 101 to the LC coating devices 210 bythe pressure of the gas (such as N₂). Subsequently, the LC coatingdevices 210 can coat the LC 101 on the transparent substrate 102,wherein the LC coating devices 210 can coat the LC 101 on thetransparent substrate 102 toward the predetermined direction.Subsequently, the real-time detectors 220 can detect the LC 101 coatedon the transparent substrate 102 and output the detection signal.Subsequently, the controller 230 can control the coating of the LCcoating devices 210 according to the detection signal. Furthermore, thecontroller 230 can control the pressure or a slit width of the slitcoating heads.

Referring to FIG. 3A again, in the second embodiment, the LC coatingdevices 210 can coat the LC 101 on a plurality of regions of thetransparent substrate 102 at the same time for forming a plurality of LCunits 103 which are cut and assembled as LC display panels. At thistime, each of the LC coating devices 210 may be configured to coat a LCunit 103, and the controller 230 can adjust the moving speed of the LCcoating devices 210, the pressure of the measuring cylinders 240, theslit width of the slit coating heads or a pitch between each two of theLC units 103 by calculating the LC amount for the LC units 103 and amoving distance in coating, so as to enhancing the uniformity of the LCfilm of each of the LC units 103. Moreover, when the LC coating devices210 move between each two of the LC units 103, the pumping device 250can pump the LC from the LC tank 260 to the measuring cylinders 240 forrenewing the LC amount thereof the measuring cylinders 240.

As described above, in comparison with the conventional LC coatingmethod, the LC coating apparatus and the LC coating method of thepresent invention can rapidly coat and form the LC film on thetransparent substrate, thereby considerably raising the productionefficiency. Furthermore, the steps of the LC coating method are verysimple, thereby reducing the labor and time. Besides, the LC coatingapparatus of the present invention can coat the LC film with highuniformity for improving the problems of bubbles or non-uniform LC film.Moreover, the LC coating apparatus includes the real-time detector toreal-time detect the coating status of the LC for precisely controllingthe LC coated amount, thickness and uniformity to improve the LC coatingquality and reduce the waste of the LC.

The present invention has been described with a preferred embodimentthereof and it is understood that many changes and modifications to thedescribed embodiment can be carried out without departing from the scopeand the spirit of the invention that is intended to be limited only bythe appended claims.

1. A liquid crystal coating apparatus, characterized in that: the liquidcrystal coating apparatus comprises: a plurality of liquid crystalcoating devices configured to coat a liquid crystal on a substrate,wherein the liquid crystal coating devices are inkjet printing heads; atleast one real-time detector disposed at one side of the liquid crystalcoating devices configured to real-time detect the liquid crystal coatedon the substrate and output a detection signal; and a controllerconfigured to adjust a voltage of the liquid crystal coating devicesaccording to the detection signal and a relation between a dropletamount and the voltage, wherein the liquid crystal amount isproportional to the voltage.
 2. The liquid crystal coating apparatusaccording to claim 1, characterized in that: the real-time detector isat least one charge coupled device configured to real-time detect theliquid crystal coated on the substrate and output the detection signalto the controller, and the detection signal is a real-time image signal,and the controller implements an image gray-scale comparison processingfor the real-time image signal outputted from the real-time detector, soas to calculate the actual weight, number, size or position of theliquid crystal coated on the substrate.
 3. A liquid crystal coatingapparatus, characterized in that: the liquid crystal coating apparatuscomprises: a plurality of liquid crystal coating devices configured tocoat a liquid crystal on a substrate, wherein the liquid crystal coatingdevices are inkjet printing heads; at least one real-time detectordisposed at one side of the liquid crystal coating devices configured toreal-time detect the liquid crystal coated on the substrate and output adetection signal; and a controller configured to control the liquidcrystal coating devices according to the detection signal.
 4. The liquidcrystal coating apparatus according to claim 3, characterized in that:the liquid crystal coating devices are piezoelectric droplet ejectors,and the controller adjusts a voltage of the liquid crystal coatingdevices according to a relation between a droplet amount and thevoltage.
 5. The liquid crystal coating apparatus according to claim 3,characterized in that: the real-time detector is at least one chargecoupled device configured to real-time detect the liquid crystal coatedon the substrate and output the detection signal to the controller, andthe detection signal is a real-time image signal, and the controllerimplements an image gray-scale comparison processing for the real-timeimage signal outputted from the real-time detector, so as to calculatethe actual weight, number, size or position of the liquid crystal coatedon the substrate.
 6. The liquid crystal coating apparatus according toclaim 3, characterized in that: the weight of each droplet of the liquidcrystal ejected by the liquid crystal coating devices is less than 0.1mg.
 7. The liquid crystal coating apparatus according to claim 3,characterized in that: a pitch between each two adjacent droplets of theliquid crystal ejected by the liquid crystal coating devices is lessthan 200 μm.
 8. A liquid crystal coating method, characterized in that:the method comprises the following steps: utilizing a plurality ofliquid crystal coating devices to coat a liquid crystal on a substrate,wherein the liquid crystal coating devices are inkjet printing heads;utilizing at least one real-time detector to real-time detect the liquidcrystal coated on the substrate and outputting a detection signal; andutilizing a controller to control the liquid crystal coating devicesaccording to the detection signal.
 9. The liquid crystal coating methodaccording to claim 8, characterized in that: the liquid crystal coatingmethod further comprises the following step: before coating the liquidcrystal on the substrate, ensuring whether a number and a weight ofliquid crystal droplets ejected by the liquid crystal coating devicessatisfy a predetermined requirement.
 10. The liquid crystal coatingmethod according to claim 8, characterized in that: the real-timedetector is at least one charge coupled device configured to real-timedetect the liquid crystal coated on the substrate and output thedetection signal to the controller, and the detection signal is areal-time image signal.
 11. The liquid crystal coating method accordingto claim 8, characterized in that: the liquid crystal coating devicesare piezoelectric droplet ejectors, and the controller calculates thenumber of the droplets of the liquid crystal ejected by the liquidcrystal coating devices according to the real-time image signal, andimplements a comparison between the number and a predetermined dropletnumber, and then adjusts the ejection of the liquid crystal coatingdevices according to a comparison result.
 12. The liquid crystal coatingmethod according to claim 8, characterized in that: the controllerimplements an image gray-scale comparison processing for the real-timeimage signal, so as to calculate the actual weight, number, size orposition of the liquid crystal coated on the substrate.